package com.wenhao.unsafe;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * @author Wenhao Tong
 * @create 2021-08-19 21:48
 */
public class SetTest {
    public static void main(String[] args) {
//        Set<String> set = new HashSet<>();

        // 解决方法1
//        Set<String> set = Collections.synchronizedSet(new HashSet<String>());

        Set<String> set = new CopyOnWriteArraySet<>();

        for (int i = 0;i < 30;i++) {
            new Thread(() -> {
                set.add(UUID.randomUUID().toString().substring(0,5));
                System.out.println(set);
            },String.valueOf(i)).start();
        }
    }
}
